WASHINGTON — The Connecticut Supreme Court on Friday gave gay and lesbian couples the right to marry, ruling that civil unions relegate them to a “separate” and “inferior status” that falls short of full equality.

“We therefore agree with the plaintiffs that maintaining a second-class-citizen status for same-sex couples by excluding them from the institution of civil marriage” violates the state’s constitutional guarantee of equal protection of the laws, the state high court said.

By a 4-3 vote, the state justices agreed with eight same-sex couples who sued after they were denied marriage licenses four years ago.

Connecticut now joins California and Massachusetts in authorizing marriage for gay and lesbian couples. In all three cases, the issue was decided in a 4-3 ruling by the state high court.

So far, no state has authorized same-sex marriage through its legislation or by a popular vote. However, on Nov. 4, California’s voters will consider Proposition 8, which seeks to overturn the state court’s ruling in May that allowed such marriages.

Attorneys on both sides of California’s same-sex marriage ballot initiative said Friday that the Connecticut ruling has no legal significance for the Proposition 8 campaign because it was based on Connecticut’s state constitution.

They agreed, however, that a ruling in a third state ﻿that legalizes same-sex marriage has social significance.

The Connecticut ruling shows “that this is really an issue for the entire nation. It really does affect the entire nation,” said Andrew Pugno, a Sacramento attorney who is general counsel for the Yes on 8 campaign.

Shannon Minter, legal director at the National Center for Lesbian Rights in San Francisco, said he hopes the Connecticut ruling will help people see that the proposed ban in California is going against the evolution of opinion elsewhere in the nation.

“I hope it will have the effect that people will see that this really is something that is inevitable,” Minter said. “Other states are also recognizing that same-sex couples have a right to marry, that treating families differently is just fundamentally unfair and harmful to those families, and harmful to our whole society.”